<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style type="text/javascript"></style>
</head>
<body>
    <script>
        let num1=1,num2=2.1;
        let  num3=1.09;
        let num=1.00;
        console.log(num);
        console.log(num3);
        console.log(typeof num1);
        console.log(typeof num2);
        console.log(num2+0.2);

        let str='熊';
        let str2='太峰';
        console.log(str+str2);
        console.log(`${str}${str2}`);
        console.log('付海剑'+1);

        let a;  //variable &a 弱类型语言 值得类型未确定 undefined
        console.log(typeof a);//undefined
        a=1;
        console.log(typeof a);

        let b=null;
        let c=undefined;

        let d=true;
//对象字面量
        let mm={
           name:'陈喵喵',
           hometown:'萍乡',
           isSignle:true
        }
        console.log(mm);
        
        var person='lili';
        person.age=22;
        person.method=function(){};
        console.log(person.age);

      
    </script>
    <script>
        function F(){}
        F.prototype.name="wewe";
        F.prototype.age=19;
        var f=new F();
        console.log(f.age);
        console.log(delete f._proto_.age);
        console.log(f.age);
    </script>
</body>
</html>